For many women and Donald Trump, the weird practice known in the Western world as the handshake is something we never master. Who cares, right? A friendly wave will do in most situations—and what with business going global, we may as well learn the art of the bow. But according to new research by University of Iowa business professor Greg Stewart, the grip is key to winning over a job interviewer.

“We’ve always heard that interviewers make up their mind about a person in the first two or three minutes of an interview, no matter how long the interview lasts,” said Stewart, associate professor of management and organizations in the Tippie College of Business. “We found that the first impression begins with a handshake that sets the tone for the rest of the interview.”

The as-yet-unpublished research was conducted with 98 students in the business school who were participating in mock job interviews with representatives from Iowa City–area businesses. The students also met at various times during their interviews with five trained handshake raters (!) who introduced themselves and shook hands—but otherwise did not participate in the interviews.

Stewart said the researchers found that those students who scored high with the handshake raters were also considered to be the most hireable by the interviewers.

Why is the handshake important?

Stewart suspects it’s because a handshake is one of the few things that provides a glimpse into the person’s individuality during the first few minutes of an interview. “Job seekers are trained how to act in a job interview, how to talk, how to dress, how to answer questions, so we all look and act alike to varying degrees because we’ve all been told the same things,” he said. “But the handshake is something that’s perhaps more individual and subtle, so it may communicate something that dress or physical appearance doesn’t.”